scholarly journals Chromatic assimilation unaffected by perceived depth of inducing light

2004 ◽  
Vol 21 (3) ◽  
pp. 373-376 ◽  
Author(s):  
STEVEN K. SHEVELL ◽  
DINGCAI CAO
Keyword(s):  
Depth Perception ◽  
Binocular Disparity ◽  
Neural Mechanism ◽  
Relative Depth ◽  
Test Field ◽  
Neural Process ◽  
Test Light ◽  
Chromatic Assimilation ◽  
Field Organization ◽  
Receptive Field Organization

Chromatic assimilation is a shift toward the color of nearby light. Several studies conclude that a neural process contributes to assimilation but the neural locus remains in question. Some studies posit a peripheral process, such as retinal receptive-field organization, while others claim the neural mechanism follows depth perception, figure/ground segregation, or perceptual grouping. The experiments here tested whether assimilation depends on a neural process that follows stereoscopic depth perception. By introducing binocular disparity, the test field judged in color was made to appear in a different depth plane than the light that induced assimilation. The chromaticity and spatial frequency of the inducing light, and the chromaticity of the test light, were varied. Chromatic assimilation was found with all inducing-light sizes and chromaticities, but the magnitude of assimilation did not depend on the perceived relative depth planes of the test and inducing fields. We found no evidence to support the view that chromatic assimilation depends on a neural process that follows binocular combination of the two eyes' signals.

scholarly journals Temporal nulling of induction from spatial patterns modulated in time

2006 ◽  
Vol 23 (3-4) ◽  
pp. 479-482 ◽  
Author(s):  
FLORENT AUTRUSSEAU ◽  
STEVEN K. SHEVELL
Keyword(s):  
Visual Cortex ◽  
Receptive Field ◽  
Spatial Patterns ◽  
Test Area ◽  
Color Appearance ◽  
Test Field ◽  
Time Varying ◽  
Field Organization ◽  
Receptive Field Organization ◽  
Negligible Influence

Temporally varying chromatic-inducing light was used to infer receptive-field organization. Time-varying shifts in color appearance within a test field were induced by a surrounding chromatic pattern; the shifts were then nulled by adding a time-varying stimulus to the test area so the observer perceived a steady test. This method measured chromatic induction without requiring an observer to judge the color appearance of the test. The induced color shifts were consistent with a +s/−s spatially antagonistic neural receptive field, which also accounts for color shifts induced by static chromatic patterns (Monnier & Shevell, 2003, Monnier & Shevell, 2004). The response of this type of receptive-field, which is found only in the visual cortex, increases with S-cone stimulation at its center and decreases with S-cone stimulation within its surround. The measurements also showed a negligible influence of temporal inducing frequency in the range 0.5–4 Hz.

Comparison of the responses of AII amacrine cells in the dark- and light-adapted rabbit retina

1999 ◽  
Vol 16 (4) ◽  
pp. 653-665 ◽  
Author(s):  
DAIYAN XIN ◽  
STEWART A. BLOOMFIELD
Keyword(s):  
Receptive Field ◽  
Light Adaptation ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Rabbit Retina ◽  
Response Component ◽  
Synaptic Inputs ◽  
Field Organization ◽  
Receptive Field Organization ◽  
Aii Amacrine Cells

We studied the light-evoked responses of AII amacrine cells in the rabbit retina under dark- and light-adapted conditions. In contrast to the results of previous studies, we found that AII cells display robust responses to light over a 6–7 log unit intensity range, well beyond the operating range of rod photoreceptors. Under dark adaptation, AII cells showed an ON-center/OFF-surround receptive-field organization. The intensity–response profile of the center-mediated response component followed a dual-limbed sigmoidal function indicating a transition from rod to cone mediation as stimulus intensities were increased. Following light adaptation, the receptive-field organization of AII cells changed dramatically. Light-adapted AII cells showed both ON- and OFF-responses to stimulation of the center receptive field, but we found no evidence for an antagonistic surround. Interestingly, the OFF-center response appeared first following rapid light adaptation and was then replaced gradually over a 1–4 min period by the emerging ON-center response component. Application of the metabotropic glutamate receptor agonist APB, the ionotropic glutamate blocker CNQX, 8-bromo-cGMP, and the nitric oxide donor SNAP all showed differential effects on the various center-mediated responses displayed by dark- and light-adapted AII cells. Taken together, these pharmacological results indicated that different synaptic circuits are responsible for the generation of the different AII cell responses. Specifically, the rod-driven ON-center responses are apparently derived from rod bipolar cell synaptic inputs, whereas the cone-driven ON-center responses arise from signals crossing the gap junctions between AII cells and ON-center cone bipolar cells. Additionally, the OFF-center response of light-adapted AII cells reflects direct synaptic inputs from OFF-center cone bipolar cells to AII dendritic processes in the distal inner plexiform layer.

Two-dimensional receptive-field organization in striate cortical neurons of the cat

1994 ◽  
Vol 11 (4) ◽  
pp. 703-720 ◽  
Author(s):  
Ming Sun ◽  
A. B. Bonds
Keyword(s):  
Receptive Field ◽  
Cortical Neurons ◽  
Ocular Dominance ◽  
Receptive Fields ◽  
Field Size ◽  
Two Dimensional ◽  
Cortical Layers ◽  
Field Organization ◽  
Receptive Field Organization ◽  
Cortical Receptive Fields

AbstractThe two-dimensional organization of receptive fields (RFs) of 44 cells in the cat visual cortex and four cells from the cat LGN was measured by stimulation with either dots or bars of light. The light bars were presented in different positions and orientations centered on the RFs. The RFs found were arbitrarily divided into four general types: Punctate, resembling DOG filters (11%); those resembling Gabor filters (9%); elongate (36%); and multipeaked-type (44%). Elongate RFs, usually found in simple cells, could show more than one excitatory band or bifurcation of excitatory regions. Although regions inhibitory to a given stimulus transition (e.g. ON) often coincided with regions excitatory to the opposite transition (e.g. OFF), this was by no means the rule. Measurements were highly repeatable and stable over periods of at least 1 h. A comparison between measurements made with dots and with bars showed reasonable matches in about 40% of the cases. In general, bar-based measurements revealed larger RFs with more structure, especially with respect to inhibitory regions. Inactivation of lower cortical layers (V-VI) by local GABA injection was found to reduce sharpness of detail and to increase both receptive-field size and noise in upper layer cells, suggesting vertically organized RF mechanisms. Across the population, some cells bore close resemblance to theoretically proposed filters, while others had a complexity that was clearly not generalizable, to the extent that they seemed more suited to detection of specific structures. We would speculate that the broadly varying forms of cat cortical receptive fields result from developmental processes akin to those that form ocular-dominance columns, but on a smaller scale.

Dynamic aspects of receptive field organization in area VI of the macaque monkey

1992 ◽  
pp. 177-188
Author(s):  
James M. Fox ◽  
David C. Van Essen ◽  
Tobias Delbrück ◽  
Jack Gallant ◽  
Charles H. Anderson
Keyword(s):  
Receptive Field ◽  
Macaque Monkey ◽  
Field Organization ◽  
Receptive Field Organization

Motion Parallax as an Independent Cue for Depth Perception

Perception ◽  
1979 ◽  
Vol 8 (2) ◽  
pp. 125-134 ◽  
Author(s):  
Brian Rogers ◽  
Maureen Graham
Keyword(s):  
Depth Perception ◽  
Close Agreement ◽  
Motion Parallax ◽  
Three Dimensional ◽  
Matching Task ◽  
Relative Depth ◽  
Relative Movement ◽  
Random Dot Stereograms ◽  
Random Dot Patterns ◽  
Dimensional Surface

The perspective transformations of the retinal image, produced by either the movement of an observer or the movement of objects in the visual world, were found to produce a reliable, consistent, and unambiguous impression of relative depth in the absence of all other cues to depth and distance. The stimulus displays consisted of computer-generated random-dot patterns that could be transformed by each movement of the observer or the display oscilloscope to simulate the relative movement information produced by a three-dimensional surface. Using a stereoscopic matching task, the second experiment showed that the perceived depth from parallax transformations is in close agreement with the degree of relative image displacement, as well as producing a compelling impression of three-dimensionality not unlike that found with random-dot stereograms.

Sensory Activation and Receptive Field Organization of the Lateral Giant Escape Neurons in Crayfish

2010 ◽  
Vol 104 (2) ◽  
pp. 675-684 ◽  
Author(s):  
Yen-Chyi Liu ◽  
Jens Herberholz
Keyword(s):  
Action Potential ◽  
Procambarus Clarkii ◽  
Receptive Fields ◽  
Sensory Information ◽  
Tactile Stimuli ◽  
Field Organization ◽  
Tail Flip ◽  
Receptive Field Organization ◽  
Sensory Activation ◽  
Stimulation Of

Crayfish ( Procambarus clarkii ) have bilateral pairs of giant interneurons that control rapid escape movements in response to predatory threats. The medial giant neurons (MGs) can be made to fire an action potential by visual or tactile stimuli directed to the front of the animal and this leads to an escape tail-flip that thrusts the animal directly backward. The lateral giant neurons (LGs) can be made to fire an action potential by strong tactile stimuli directed to the rear of the animal, and this produces flexions of the abdomen that propel the crayfish upward and forward. These observations have led to the notion that the receptive fields of the giant neurons are locally restricted and do not overlap with each other. Using extra- and intracellular electrophysiology in whole animal preparations of juvenile crayfish, we found that the receptive fields of the LGs are far more extensive than previously assumed. The LGs receive excitatory inputs from descending interneurons originating in the brain; these interneurons can be activated by stimulation of the antenna II nerve or the protocerebral tract. In our experiments, descending inputs alone could not cause action potentials in the LGs, but when paired with excitatory postsynaptic potentials elicited by stimulation of tail afferents, the inputs summed to yield firing. Thus the LG escape neurons integrate sensory information received through both rostral and caudal receptive fields, and excitatory inputs that are activated rostrally can bring the LGs' membrane potential closer to threshold. This enhances the animal's sensitivity to an approaching predator, a finding that may generalize to other species with similarly organized escape systems.

Effects of nerve injury on sympathetic excitation of A delta mechanical nociceptors

1995 ◽  
Vol 73 (4) ◽  
pp. 1721-1723 ◽  
Author(s):  
D. F. Bossut ◽  
E. R. Perl
Keyword(s):  
Receptive Field ◽  
Nerve Injury ◽  
High Threshold ◽  
Myelinated Fiber ◽  
Mechanical Stimuli ◽  
Sympathetic Stimulation ◽  
Great Auricular Nerve ◽  
C Fiber ◽  
Field Organization ◽  
Receptive Field Organization

1. The effects of sympathetic stimulation and close arterial injection of norepinephrine were tested on cutaneous myelinated-fiber (A delta) mechanical nociceptors [high-threshold mechanoreceptors-(MyHTMs)] from normal and from partially transsected nerves. 2. Neither sympathetic stimulation nor close arterial injection of norepinephrine (200 ng) excited MyHTMs (18) recorded from the uninjured great auricular nerve of adult rabbits. 3. MyHTMs (58) conducting across the site of partial cut lesions, made 2 to 28 days previously, had threshold and responsiveness to mechanical stimuli, receptive field organization, and absence of background discharge typical of such elements in normal nerve. 4. Four MyHTMs recorded from the injured nerves were excited by sympathetic stimulation and/or norepinephrine injection but only one gave more than two impulses within 60 s to either form of stimulation. 5. The meagerness of the sympathetic and adrenergic excitation of MyHTMs after nerve injury contrasts with that observed under similar conditions for C-fiber polymodal nociceptors. Therefore, induction of adrenergic responsiveness in nociceptors after partial denervation in cutaneous MyHTMs appears to be less important for mechanisms related to pathogenic pain than alterations in certain C-fiber nociceptors.

Quantitative Measurement of Human Visual Characteristic on Depth Perception with Using Random-Dot Stimulus

2000 ◽  
Vol 44 (21) ◽  
pp. 3-500-3-500
Author(s):  
Jing-Long Wu ◽  
Kazuyoshi Tsukamoto
Keyword(s):  
Depth Perception ◽  
Quantitative Measurement ◽  
Binocular Disparity ◽  
Experimental Results ◽  
Depth Information ◽  
Head Mounted Display ◽  
Visual Characteristic

Human interactive characteristic between the binocular disparity and the occlusion for depth perception is measured with using random-dot stimulus. The experimental results suggested that if the binocular disparity is set at a proper value, the depth information is mainly obtained from the cue of the binocular disparity, and if the occlusion ratio is larger than some constant value the depth information is obtained from the cue of the occlusion. Based on the experimental results, we can find a method to make images with depth information in the Head Mounted Display (HMD) when the cues of the binocular disparity and the occlusion are concurrently used.

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